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Al writes "An engineer from Nokia's UK research labs says that the company is developing technology that can harvest ambient electromagnetic radiation to keep a cellphone going. The researcher says that his group is working towards a prototype that could harvest up to 50 milliwatts of power — enough to slowly recharge a phone that is switched off. He says current prototypes can harvest 3 to 5 milliwatts. It will require a wideband receiver capable of capturing signals from between 500 megahertz and 10 gigahertz — a range that encompasses many different radio communication signals. Other researchers have developed devices that can harvest more modest power from select frequencies. A team from Intel previously developed a compact sensor capable of drawing 6 microwatts from a 1.0-megawatt TV antenna 4.1 kilometers away."

It's called a lightning rod, although a clock tower and a sufficient length of cable will work in a pinch. Figuring out how to get lightning to strike a DeLorian while traveling at 88mph is left as an exercise for the reader.

This is useful knowledge to have. Imagine being lost and in need of rescue. If you could create a device that siphoned sufficient power from radio signals to reduce their range, not only would you have power for a beacon but also the FCC would take care of tracking down your location so that you'd stop doing it.

I have geraniums but they don't act as radio receivers, nor transmitters. They don't appear to make noise either. They just grow up until they're spindly because I forget to nip the buds out. Nice red flowers though.

You'll have to select a power company and only get power from them. They'll find some way to track your usage (probably an electric chip on the device which... requires power).

Now to keep power sorted out right, each company will get their own frequency. It will be against the SDMCAaPDA (Super-DMCA and Puppy Disbursement Act) to explain to anyone the concept of an antenna or a diode, as those could be used to steal power.

But don't worry, they'll make the power broadcast towers look like 50 foot tall lamp-posts so they will "blend in" to the scenery and not be an eyesore.

What, I must have cheated when I watch this documentary about time travel several years ago.

That's odd, I wasn't going to start producing any documentary until next year. I guess it works. Uh, will work. Will have worked? Damnit, I have a hard enough time trying to get regular-flow grammar right, and now I'm going to have to lear it all over again.

You have to extract the dye from the geranium flowers, then use it to build a continuous dye laser which you modulate with the incoming RF signal. The beam is aimed at a very fast response bolometer which provides rectification. Just amplify the signal from a small current through the bolometer to get audio output.

This is an easy project for a 16 year old provided mummy or daddy is a full professor of physics at Stanford.